Sipilä, Tero, and Heikki Hyvärinen. “Status and biology of Saimaa (<i>Phoca hispida saimensis</i>) and Ladoga (<i>Phoca hispida ladogensis</i>) ringed seals”. NAMMCO Scientific Publications 1 (June 5, 1998): 83–99. Accessed January 8, 2025. https://new.eludamos.org/index.php/NAMMCOSP/article/view/2982.